Association of coronary artery calcification with obstructive sleep apnea and obesity in middle-aged men

Association between apnea-hypopnea index and coronary artery calcification: a systematic review and meta-analysis

BACKGROUND

The present study aimed to evaluate the association between presence and severity of obstructive sleep apnoea (OSA) and the presence of subclinical coronary artery disease (CAD) as assessed by coronary calcium score.

METHODS

Medline, Cochrane, and Google Scholar databases were searched. The presence of coronary artery calcification (CAC) and CAC score were assessed.

RESULTS

Irrespective of the cut-off value of apnoea-hypopnea index (AHI) (5 or 15 events/h), patients in the OSA group had higher rate of CAC presence and mean CAC score than those in the control group. Subgroup analyses of patients monitored with home sleep apnoea testing (HSAT) or in-hospital/laboratory polysomnography showed that the OSA group had higher rate of CAC presence and mean CAC score than the control group, except in the comparison of mean CAC score between AHI ≥5 vs. <5 events/h for patients using HSAT, which was not significant. Pair-wise comparison showed that CAC score may increase with increased OSA severity.

CONCLUSIONS

In participants without symptomatic coronary disease, the presence of OSA was associated with the presence and extent of CAC. However, potential confounders such as age, gender, and BMI and the diversity of CAC scores may affect the association.

Obstructive sleep apnea increases the risk of cardiovascular damage: a systematic review and meta-analysis of imaging studies

BACKGROUND

We aimed to perform a systematic review and meta-analysis of the association between obstructive sleep apnea (OSA) and cardiac as well as coronary impairment evaluated using imaging modalities. Finding of this study will provide more robust evidence regarding OSA-induced cardiovascular damage.

METHODS

We systematically searched through PubMed, EMBASE, and Cochrane library databases for relevant literatures on the association between OSA and cardiovascular damage evaluated using imaging modalities, and manually searched the references of selected articles for additional relevant articles. For each clinical parameter relevant to the meta-analysis, we first evaluated the methodological heterogeneity of the relevant studies and thereafter pooled the data together using fixed effect or random effect model. The difference in the relevant indices of cardiovascular damage between OSA patients and controls was evaluated using the standardized mean difference.

RESULTS

Of the 82 articles included in the final systematic analysis, 20 studies explored the association between OSA and coronary atherosclerosis. OSA patients had higher rate of coronary atherosclerosis assessed by coronary artery calcification score and plaque volume. Moreover, the severity of OSA and coronary atherosclerosis displayed a positive correlation. The rest of the studies (n = 62) evaluated cardiac alterations in OSA patients. According to the inclusion and exclusion criteria, 46 studies yielding 3082 OSA patients and 1774 controls were pooled for the meta-analysis. For left cardiac structure and function, OSA patients exhibited significantly wider left atrial diameter; higher left atrium volume index; wider left ventricular end-systolic diameter, left ventricular end-diastolic diameter, and left ventricular mass; higher left ventricular mass index; wider interventricular septum diameter and posterior wall diameter; and higher left ventricular myocardial performance index (all p < 0.05). In addition, compared with controls, left ventricular ejection fraction was significantly decreased in OSA patients (p = 0.001). For right cardiac structure and function, OSA patients displayed a significant increase in right ventricular diameter and right ventricular myocardial performance index (both p < 0.001). Finally, compared with controls, OSA patients displayed significant decrease in tricuspid annular plane systolic excursion and RV fractional area change (p = 0.001).

CONCLUSION

Overall, this systematic review and meta-analysis provides imaging evidence in support that OSA patients are at a higher risk of developing coronary atherosclerosis and display cardiac remodeling and dysfunction.

Sleep apnea, coronary artery calcium density and cardiovascular events: results from the Multi-Ethnic Study of Atherosclerosis (MESA)

STUDY OBJECTIVES

Evaluate the association between obstructive sleep apnea (OSA), coronary artery calcium (CAC) density, and cardiovascular events in the Multi-Ethnic Study of Atherosclerosis (MESA).

METHODS

We analyzed 1041 participants with non-zero CAC scores who had polysomnography and CAC density data from the fifth examination of MESA. OSA was defined as apnea-hypopnea index [AHI] ≥ 15 events/hour. Multivariable linear regression models were used to evaluate the independent association between OSA and CAC density. Additionally, we evaluated the impact of OSA on associations of CAC measures with incident CVD events by testing for interaction in Cox proportional hazard regression models.

RESULTS

Our analytical sample was 45% female with a mean age of 70.6 +/- 9 years. Of this sample, 36.7% (n=383/1041) had OSA (AHI≥15). OSA was inversely and weakly associated with CAC density (β= -0.09, 95% CI -0.17 to -0.02, p=0.014) and remained significantly associated after controlling for traditional cardiovascular risk factors (β= -0.08, 95% CI -0.16 to 0, p=0.043). However, this inverse association was attenuated after controlling for BMI (β=-0.05, 95% CI -0.13 to 0.02, p=0.174). The mean follow-up period for CVD events was 13.3 +/- 2.8 years. Additionally, exploratory analysis demonstrated that CAC density was independently and inversely associated with CVD events only in the non-OSA subgroup (AHI≤15) (HR 0.509 [CI 0.323 - 0.801], p=0.0035).

CONCLUSIONS

OSA was associated with lower CAC density, but this association was attenuated by BMI. Further, increased CAC density was associated with a reduced risk of CVD events only in individuals within the non-OSA group in exploratory analysis.

Hypoxemia During Sleep and the Progression of Coronary Artery Calcium

The aim of this study was to evaluate the associations between objective sleep parameters of obstructive sleep apnea (OSA) and progression of subclinical cardiovascular disease as measured by the coronary artery calcium (CAC) score. We reviewed the medical records of 196 patients who underwent both polysomnography (PSG) and repeated coronary artery computed tomography (CT) for screening purposes. For each participant, the first coronary CT scan was conducted within 12 months of PSG. Follow-up CT was performed voluntarily. The CAC score was log-transformed to obtain normally distributed data. We evaluated potential associations between various sleep parameters by analyzing overnight-attended PSG and CAC score progression over time. ST90 (total sleep time of SaO₂ < 90%), CT90 (percentage of time of SaO₂ < 90%), and degree of mean oxygen desaturation were significantly correlated with CAC score progression even after adjustment for confounders (age, sex, DM, HTN, hypercholesterolemia, BMI, and smoking status) (estimate = 0.004, p = .010; estimate = 0.009, p < .001; estimate = 0.027, p = .001; respectively). We also performed subgroup analysis and found that the progression of CAC score over time showed higher tendency when CT90 value was 2.73 or more (CT90 ≥ 2.73 group; estimate = 0.336, CT90 < 2.73 group; estimate = 0.194, p < .001 each). ST90, CT90 and mean oxygen desaturation are significant predictors of cardiovascular disease progression. Coronary artery status should be monitored repetitively in patients with hypoxemia during sleep.

Relationship of obstructive sleep apnoea severity and subclinical systemic atherosclerosis

Obstructive sleep apnoea (OSA) is a common form of sleep disordered breathing. Untreated OSA might accelerate atherosclerosis, potentially increasing the cardiovascular disease burden in patients. The present study aimed to evaluate the association between objectively measured OSA severity and the presence of subclinical systemic atherosclerosis using noninvasive measurements, including tomographic quantification of the calcium burden.A total of 2157 participants of the Korean Genome and Epidemiology Study, who were free of structural heart disease and underwent both in-home polysomnography and chest computed tomography, were cross-sectionally analysed. Participants were divided into three groups based on the severity of OSA: no OSA (apnoea-hypopnoea index (AHI) <5 events·h^-1, n=1096), mild OSA (AHI 5- <15 events·h^-1, n=700) and moderate-to-severe OSA (AHI ≥15 events·h^-1, n=361). Calcium deposits in the thoracic aorta and coronary arteries were measured by the Agatston score.Participants with moderate-to-severe OSA were 1.6 times (95% CI 1.18-2.15 times; p=0.002) more likely to have ascending thoracic aorta calcification (≥100 units) than those without OSA, after adjustment for cardiovascular risk factors. In addition, the association between moderate-to-severe OSA and ascending thoracic aorta calcification of subjects with higher epicardial fat volume was slightly stronger than that in patients without OSA and in the lowest epicardial fat volume tertile (OR 2.11, 95% CI 1.30-3.43).Severity of OSA in the general population was independently associated with subclinical systemic atherosclerosis. These findings highlight the potential importance of severe OSA, especially in subjects with higher epicardial fat, as a possible predictive factor for systemic atherosclerosis and cardiovascular disease.

Obstructive sleep apnea risk and subclinical atherosclerosis in South Asians living in the United States

OBJECTIVES

The objective of this study was to examine the association between high risk of obstructive sleep apnea (OSA) and subclinical atherosclerosis among South Asians in the United States.

DESIGN

A secondary analysis of cross-sectional data.

SETTING/PARTICIPANTS

A community-based cohort of 906 men and women participating in the Mediators of Atherosclerosis in South Asians Living in America (MASALA) study.

MEASUREMENTS

The Berlin Questionnaire was used to screen for OSA risk. Coronary artery calcium (CAC), common carotid artery intima-media thickness (IMT), and internal carotid artery IMT were used as measures of subclinical atherosclerosis.

RESULTS

The majority of participants (59%) with high OSA risk had CAC scores >0 compared with only 41% of participants with low OSA risk (P <.001). The high OSA risk group was older (P =.005), male (P =.04), had higher body mass index (P <.001) and had greater common carotid artery IMT (0.96 ± 0.27 mm) and internal carotid artery IMT (1.33 ± 0.42 mm) measurements. Snoring, sleep-disordered breathing (SDB), and high OSA risk were associated with subclinical atherosclerosis. However, only high OSA risk remained significant in multivariable models after controlling for demographic and clinical factors that included hypertension (HTN), obesity, diabetes, and dyslipidemia.

CONCLUSIONS

High OSA risk, which includes overlapping comorbidities of HTN and obesity, was not associated with the time living in the US but was associated with subclinical atherosclerosis markers. These cardiovascular disease risk factors should include evaluation of the spectrum of SDB among all adults, including South Asian men and women.

Comprehensive coronary plaque assessment in patients with obstructive sleep apnea

Obstructive sleep apnea (OSA) is associated with an increased risk of cardiovascular disease. Previous studies have assessed the relationship between OSA and coronary artery disease (CAD) using coronary artery calcium score (CAC) measurements. However, limited data are available regarding the association of OSA with non-calcified plaque burden. We therefore aimed to assess the relationship between CAD severity as assessed by coronary computed tomography angiography (CTA) and OSA. Forty-one adult subjects (59 ± 9 years, 15 men) underwent a 256-slice coronary CTA, which was followed by a diagnostic attended cardiorespiratory polygraphy (n = 13) or polysomnography (n = 28). Segment involvement score (SIS), segment stenosis score (SSS) and CAC were used to quantify total CAD burden. Correlation analysis was used to assess potential associations between CAD and OSA. Twenty-two patients were diagnosed with OSA. SIS and SSS were elevated in OSA (2.90 ± 2.78 versus 1.79 ± 2.39 and 4.91 ± 5.94 versus 1.79 ± 4.54, OSA versus controls, SIS and SSS respectively, both p < 0.01) and correlated with OSA severity as measured by the apnea-hypopnea index (AHI, r = 0.41 and 0.43, p < 0.01) and oxygen desaturation index (ODI, r = 0.45 and 0.46, p < 0.01). However, no significant correlation was observed between CAC and OSA. Compared to CAC, SIS and SSS provide additional information on coronary plaque burden in OSA, which shows a significant association with OSA.

Association of High-Sensitivity Troponin T With Left Ventricular Dysfunction in Ankylosing Spondylitis

BACKGROUND

Ankylosing spondylitis (AS) is a systemic inflammatory disease, and cardiac dysfunction has not been clearly described clinically. High-sensitivity cardiac troponin T (hs-cTnT) is a noninvasive marker for subclinical myocardial injury.

OBJECTIVE

In this study, we aimed to investigate any relationship between hs-cTnT and left ventricular (LV) function evaluated via tissue Doppler imaging in AS patients with no known cardiac risk factor.

METHODS

Our study used a cross-sectional case protocol design and was conducted between January 2016 and June 2016. In total, 40 AS patients (17 females and 23 males) were age and sex matched with healthy volunteers (20 females and 20 males) and enlisted for this study. Detailed transthoracic echocardiography was performed, and tissue Doppler imaging was used to assess systolic and diastolic functions. High-sensitivity cardiac troponin T levels were measured and compared between 2 groups.

RESULTS

Compared with control subjects, AS patients had lower early (Em)/late (Am) diastolic myocardial velocities, mitral annular plane systolic excursion, and end-diastolic distance from the mitral annulus to the LV apex. Conversely, they had greater systolic myocardial velocity (Sm), isovolumetric relaxation time, and displacement index (p < 0.001, for all). Higher hs-cTnT levels were measured in AS patients (0.45 ± 0.22 vs. 1.11 ± 0.27, p < 0.001), and multivariate logistic regression analyses revealed that hs-cTnT was an independent predictor of LV diastolic dysfunction in AS patients.

CONCLUSIONS

These data show that AS patients had impaired LV functions and increased hs-cTnT levels. Tissue Doppler imaging may be a useful tool for detection of early functional LV abnormalities, and hs-cTnT may be valuable biomarker of diastolic LV dysfunction in AS patients.

Association of Obstructive Sleep Apnea With Subclinical Cardiovascular Disease Predicted by Coronary Artery Calcium Score in Asymptomatic Subjects

The aim of this study is to determine the association among various sleep parameters for obstructive sleep apnea (OSA) and subclinical cardiovascular disease measured by coronary artery calcium (CAC) score. A cross-sectional study was conducted among 461 patients who underwent both polysomnography (PSG) and coronary artery computed tomography to evaluate CAC score. For each participant, coronary artery computed tomography was conducted within 12 months of PSG. We evaluated the possible association among various PSG parameters by evaluating overnight-attended PSG and CAC. A univariate analysis with lowest SaO₂ and stage 3 sleep % during sleep was significantly associated with CAC score (β = -5.528, 95% confidence interval [CI] -9.179 to -1.777, p = 0.004 and β = -8.658, 95% CI -16.461 to -0.855, p = 0.030, respectively). However, after adjustment for possible confounders, only the lowest SaO₂ was independently associated with CAC score (β = -5.234, 95% CI -9.215 to -1.253, p = 0.010). This association was stronger in participants aged ≥60 years (β = -26.966, 95% CI -41.874 to -12.058, p = 0.001). In a univariate analysis, apnea-hypopnea index, stage 3 sleep %, and moderate and severe OSA were significantly associated with CAC presence (odds ratio [OR] 1.010, p = 0.035; OR 0.949, p = 0.039; OR 2.186, p = 0.013; and OR 2.019, p = 0.020, respectively). However, after adjusting for possible confounders, there was no significant association. In conclusion, the patients with intermittent hypoxemia during sleep should be considered for evaluation of coronary artery calcification to detect cardiovascular disease in subclinical status.

Objectively measured sleep characteristics and prevalence of coronary artery calcification: the Multi-Ethnic Study of Atherosclerosis Sleep study

BACKGROUND

We tested whether objectively measured indices of obstructive sleep apnoea (OSA) and sleep quality are associated with coronary artery calcification (CAC) prevalence independent of obesity, a classic confounder.

METHODS

1465 Multi-Ethnic Study of Atherosclerosis participants (mean age 68 years), who were free of clinical cardiovascular disease, had both coronary CT and in-home polysomnography and actigraphy performed. OSA categories were defined by the Apnea-Hypopnea Index (AHI). Prevalence ratios (PRs) for CAC >0 and >400 (high burden) were calculated.

RESULTS

Participants with severe OSA (AHI ≥30; 14.6%) were more likely to have prevalent CAC, relative to those with no evidence of OSA, after adjustment for demographics and smoking status (PR 1.16; 95% CI 1.06 to 1.26), body mass index (1.11; 1.02 to 1.21) and traditional cardiovascular risk factors (1.10; 1.01 to 1.19). Other markers of hypoxaemia tended to be associated with a higher prevalence of CAC >0. For CAC >400, a higher prevalence was observed with both a higher arousal index and less slow-wave sleep. Overall, associations were somewhat stronger among younger participants, but did not vary by sex or race/ethnicity.

CONCLUSIONS

In this population-based multi-ethnic sample, severe OSA was associated with subclinical coronary artery disease (CAC >0), independent of obesity and traditional cardiovascular risk factors. Furthermore, the associations of the arousal index and slow-wave sleep with high CAC burden suggest that higher nightly sympathetic nervous system activation is also a risk factor. These findings highlight the potential importance of measuring disturbances in OSA as well as sleep fragmentation as possible risk factors for coronary artery disease.

Relation of obstructive sleep apnea to coronary artery calcium in non-obese versus obese men and women aged 45-75 years

Sleep apnea and obesity are strongly associated, and both increase the risk for coronary artery disease. Several cross-sectional studies have reported discrepant results regarding the role obesity plays in the relation between sleep apnea and coronary artery calcium (CAC), a marker of subclinical coronary disease. The aim of the present study was to investigate the association between sleep apnea and the presence of CAC in a community cohort of middle-aged men and women without preexisting cardiovascular disease, stratified by body mass index (<30 vs ≥30 kg/m(2)). Participants underwent electron-beam computed tomography to measure CAC and underwent home sleep testing for sleep apnea. The presence of CAC was defined as an Agatston score >0. Sleep apnea was analyzed categorically using the apnea-hypopnea index. The sample was composed of primarily men (61%) and Caucasians (56%), with a mean age of 61 years. The prevalence of CAC was 76%. In participants with body mass indexes <30 kg/m(2) (n = 139), apnea-hypopnea index ≥15 (vs <5) was associated with 2.7-fold odds of having CAC, but the effect only approached significance. Conversely, in participants with body mass indexes ≥30 kg/m(2), sleep apnea was not independently associated with CAC. In conclusion, sleep apnea is independently associated with early atherosclerotic plaque burden in nonobese patients.

Obstructive sleep apnea and progression of coronary artery calcium: the multi-ethnic study of atherosclerosis study

Background

Obstructive sleep apnea (OSA) is a common condition associated with cardiovascular disease. Its potential effect on progression of subclinical atherosclerosis is not well understood. We tested the hypothesis that self‐reported OSA is associated with progression of coronary artery calcium (CAC). We also evaluated whether traditional cardiovascular risk factors accounted for the association.

Methods and Results

In the Multi‐Ethnic Study of Atherosclerosis (MESA) prospective cohort, we studied 2603 participants who at baseline (2002–2004) completed a sleep questionnaire and underwent coronary computed tomography (CT) and, then 8 years later (2010–2011), a repeat coronary CT. Participants were categorized by symptoms of habitual snoring or reported physician diagnosis of OSA. At baseline, 102 (3.9%) reported diagnosed OSA; 666 (25.6%) reported diagnosed habitual snoring; and 1835 (70.5%) reported neither habitual snoring nor OSA (“normal”). At baseline, CAC prevalence was highest among those with OSA but similar for those with and without habitual snoring. During 8 years of follow‐up, greater progression of CAC was observed among those with OSA versus normal (mean increase of 204.2 versus 135.5 Agatston units; P=0.01), after accounting for demographics, behaviors, and body habitus. Modest attenuation was observed after adjustment for cardiovascular risk factors (188.7 versus 138.8; P=0.06). CAC progression among habitual snorers was similar to that observed in the normal group.

Conclusions

OSA was associated with CAC score progression after adjustment for demographics, behaviors, and body mass index. However, the association was not significant after accounting for cardiovascular risk factors, which may mediate the association between OSA and CAC.

Systematic review on noninvasive assessment of subclinical cardiovascular disease in obstructive sleep apnea: new kid on the block!

Patients with obstructive sleep apnea (OSA) have a high burden of cardiovascular disease (CVD) but a causal relationship between OSA and atherosclerotic CVD remains unclear. We systematically reviewed the literature analyzing the relationship. A review of the Medline database for studies noninvasively evaluating subclinical CVD in OSA was conducted. A total of fifty-two studies were included in this review. Across the studies the prevalence of atherosclerosis, as assessed by coronary artery calcification, carotid intima-media thickness, brachial artery flow-mediated dilation and pulse wave velocity was higher in patients with OSA and correlated with increasing severity and duration of OSA. This study shows OSA is an independent predictor of subclinical CVD as CVD is more likely to occur in patients with long standing and severe OSA. Further research is however necessary to identify specific OSA populations that would benefit from aggressive screening.

Association of obstructive sleep apnoea with subclinical coronary atherosclerosis

BACKGROUND

Accumulating evidence suggests a role of obstructive sleep apnoea (OSA) as a risk factor for coronary atherosclerosis. This study aimed i) to assess the prevalence of OSA in the general population and ii) to analyse the association of this disorder with traditional cardiovascular disease risk factors and subclinical coronary atherosclerosis.

METHODS

In a cross-sectional analysis of the Heinz Nixdorf Recall study a subgroup of 1604 subjects (791 men, age 50-80 years) underwent OSA screening. Furthermore, coronary artery calcium (CAC) was measured. OSA was defined as apnoea-hypopnoea index (AHI) ≥ 15/h.

RESULTS

OSA was observed in 29.1% of men and 15.6% of women. In a multiple linear regression analysis adjusted for risk factors AHI was associated with CAC in men aged ≤65 years (estimated log-transformed increase of CAC = 0.25, 95% confidence interval (CI) = -0.001-0.50, p = 0.051) and in women of any age (estimated log-transformed increase = 0.23, 95% CI = 0.04-0.41, p = 0.02). Doubling of the AHI was associated with a 19% increase of CAC in men aged ≤65 years and with a 17% increase in women of any age.

CONCLUSIONS

In the general population aged ≥50 years OSA is associated with subclinical atherosclerosis in men aged ≤65 years and in women of any age, independent of traditional cardiovascular risk factors.

Do reports of sleep disturbance relate to coronary and aortic calcification in healthy middle-aged women?: Study of women's health across the nation

BACKGROUND

Poor sleep may be associated with the cardiovascular disease (CVD) morbidity and mortality. It is less clear if poor sleep is associated with subclinical CVD. We evaluated cross-sectional associations between self-reported sleep disturbance and duration and calcification in the coronary arteries (CAC) and aorta (AC) in healthy mid-life women.

METHODS

512 black and white women enrolled in the SWAN Heart Study, underwent a computed tomography protocol for measurement of CAC and AC and completed questionnaires about their sleep. Linear and partial proportional logit regression analyses adjusted for site, race, age, body mass index, and the Framingham risk score (model 1). Additional covariates of education, perceived health, hypnotic medication and alcohol use were evaluated (model 2), plus depressive symptoms (model 3).

RESULTS

AC was related to higher levels of trouble falling asleep, waking earlier than planned, overall poor sleep quality, and cough/snoring and shorter sleep duration in linear regression analyses (model 1). Adjustments for additional covariates showed that poor sleep quality and waking earlier than planned remained associated with higher AC (models 2 and 3). CAC was unrelated to sleep characteristics.

CONCLUSIONS

Poor sleep quality is related to AC in middle-aged women. Sleep quality should routinely be assessed in mid-life women.

Chlamydia pneumoniae and progression of subclinical atherosclerosis

BACKGROUND

Cross-sectional investigation between presence of antibodies and coronary artery calcification (CAC) in past studies has shown no relationship, but progression over time has not been investigated. The objective of this study was to determine the relationship between presence of Chlamydia pneumoniae antibodies and progression of CAC and ankle-brachial index (ABI).

DESIGN

The Multiethnic Study of Atherosclerosis (MESA) is a prospective population-based cohort of racially and ethnically diverse male and female participants recruited from six communities in the USA, age 45-84 years, free of clinical cardiovascular disease at baseline.

METHODS

The main outcomes were progression of mean CAC and ABI between exams 1 (2000-02) and 3 (2004-05) (median follow-up of 3.13 years) by C. pneumoniae antibody. Multivariate models adjusting for demographics, obesity, smoking, alcohol use, and physical activity were computed.

RESULTS

Of 2223 subjects analysed, 76% were positive for C. pneumoniae antibodies. Progression of CAC was significantly higher in the antibody-positive group (93.8 vs. 78.2 agatston units, p = 0.02) and in antibody-positive subjects with CAC ≥10 at baseline (216.5 vs. 178.6, p = 0.02) than antibody-negative group. Smoking and body mass index ≥30 kg/m(2) both had interactions with presence of C. pneumoniae yielding significantly greater CAC progression. Progression of ABI did not significantly differ by C. pneumoniae antibody status in models adjusted for covariates.

CONCLUSIONS

C. pneumoniae antibodies are related to progression of CAC, particularly in individuals with CAC present at baseline. This provides evidence that certain groups are at higher risk of atherosclerotic progression and may be useful for risk stratification and treatment.

Obstructive sleep apnea syndrome (OSAS) and hypertension: pathogenic mechanisms and possible therapeutic approaches

Obstructive sleep apnea syndrome (OSAS), a chronic condition characterized by collapse of the pharynx during sleep, has been increasingly recognized as a health issue of growing importance over the last decade. Recently emerging evidence suggests that there is a causal link between OSAS and hypertension, and hypertension represents an independent risk factor in OSAS patients. However, the pathophysiological basis for patients with OSAS having an increased risk for hypertension remains to be elucidated. The main acute physiological outcomes of OSAS are intermittent hypoxia, intrapleural pressure changes, and arousal from sleep, which might induce endothelial dysfunction, sympathetic activation, renin-angiotensin-aldosterone system activation, lipid metabolism dysfunction, and increased oxidative stress. This brief review focuses on the current understanding of the complex association between OSAS and hypertension.

Independent association between obstructive sleep apnea and noncalcified coronary plaque demonstrated by noninvasive coronary computed tomography angiography

BACKGROUND

Coronary artery atherosclerosis has been associated with obstructive sleep apnea (OSA). However, the type and severity of plaque formation have not been characterized. This study evaluated the association of coronary noncalcified plaques and severity of stenosis in patients with OSA.

HYPOTHESIS

METHODS

This study was a retrospective analysis of 81 patients, 49 with OSA and 32 without OSA, who had undergone multidetector-row helical computed tomography scanning. The board-certified radiologist was blinded to the diagnosis of OSA and reviewed the scans for plaque characterization, severity of stenosis, and number of vessels involved.

RESULTS

Of the 81 patients reviewed, the mean apnea-hypopnea index in the OSA group was 42.2 vs 7.5 in the non-OSA group. The groups did not significantly differ in the distribution of comorbid conditions. We found that among the patients with OSA, 63% had noncalcified/mixed plaques, as opposed to 16% in the non-OSA group (P < 0.0001), with unadjusted odds ratio of 9.3 (3.0, 28.4). After adjustment for other risk factors such as age, sex, race, hypercholesterolemia, and history of smoking, the association remained strong, with an odds ratio of 7.0 (1.9, 26.5; P < 0.05).

CONCLUSIONS

Our study finds that the frequency of noncalcified/mixed plaques is much higher in patients with OSA than in non-OSA patients. Patients with OSA also have more severe stenosis and a higher number of vessels involved. This study adds to a growing body of data regarding our understanding of the association of OSA and atherosclerosis.

Obstructive sleep apnea hypopnea syndrome and metabolic syndrome: a synergistic cardiovascular risk factor

PURPOSE

Cardiovascular disease (CVD) is the leading cause of morbidity and mortality for adults in the United States. One risk factor for CVD is metabolic syndrome, which encompasses obesity, hypertension, insulin resistance, proinflammatory state, and prothrombotic state. A lesser-understood risk factor is obstructive sleep apnea hypopnea syndrome (OSAHS). This article explores the physiological consequences of the interaction between OSAHS and metabolic syndrome on the cardiovascular system.

DATA SOURCES

Search terms "metabolic syndrome,""obstructive sleep apnea,""cardiovascular disease,""diabetes,""obesity," and "atherosclerosis," were used. Studies involving children were excluded.

CONCLUSIONS

Both metabolic syndrome and OSAHS have significant impact on the cardiovascular system; however, when both conditions are present together, the impact is synergistic and CVD risk is multiplied. Treatment with continuous positive airway pressure (CPAP) reduces the global burden of CVD risk.

IMPLICATIONS FOR PRACTICE

Providers need to screen patients routinely for both metabolic syndrome and OSAHS. Treatment should include CPAP, weight reduction, oral appliances, and/or upper airway surgeries with concurrent management for metabolic syndrome. Future research should further elucidate the mechanisms of action by which OSAHA and metabolic syndrome contribute to CVD. This understanding can lead to more stringent guidelines on the management of metabolic syndrome and OSAHS.

Obstructive sleep apnea: an emerging risk factor for atherosclerosis

Obstructive sleep apnea (OSA) is independently associated with death from cardiovascular diseases, including myocardial infarction and stroke. Myocardial infarction and stroke are complications of atherosclerosis; therefore, over the last decade investigators have tried to unravel relationships between OSA and atherosclerosis. OSA may accelerate atherosclerosis by exacerbating key atherogenic risk factors. For instance, OSA is a recognized secondary cause of hypertension and may contribute to insulin resistance, diabetes, and dyslipidemia. In addition, clinical data and experimental evidence in animal models suggest that OSA can have direct proatherogenic effects inducing systemic inflammation, oxidative stress, vascular smooth cell activation, increased adhesion molecule expression, monocyte/lymphocyte activation, increased lipid loading in macrophages, lipid peroxidation, and endothelial dysfunction. Several cross-sectional studies have shown consistently that OSA is independently associated with surrogate markers of premature atherosclerosis, most of them in the carotid bed. Moreover, OSA treatment with continuous positive airway pressure may attenuate carotid atherosclerosis, as has been shown in a randomized clinical trial. This review provides an update on the role of OSA in atherogenesis and highlights future perspectives in this important research area.

Associations of Framingham risk score profile and coronary artery calcification with sleep characteristics in middle-aged men and women: Pittsburgh SleepSCORE study

BACKGROUND

Short and less efficient sleep may be risk factors for atherosclerosis. Few studies have investigated the associations between sleep characteristics and early cardiovascular disease (CVD) risk.

OBJECTIVE

Evaluate the associations between coronary artery calcification (CAC) and Framingham risk score profile with sleep characteristics in middle-aged men and women with no history of diagnosed myocardial infarction, interventional cardiology procedures, stroke, diabetes, or sleep disorders.

METHOD

224 participants enrolled in an epidemiological study of disparities in CVD risk were recruited for a 9-night assessment of sleep, with 2 nights of polysomnography (PSG) and 9 nights of actigraphy and sleep diaries. Of the 224 participants, 110 had high/moderate Framingham risk scores and 114 had low scores; 195 had computed tomography measures of CAC.

RESULTS

Individuals who had any CAC or higher Framingham risk scores had elevated apnea/hypopnea index (AHI) values, independent of age, race, and gender. The AHI association with CAC was nonsignificant in analyses adjusting for body mass index (BMI). Those with higher Framingham risk score profiles had shorter PSG sleep duration and less percent stage 3-4 and delta power sleep. High blood pressure and left ventricular hypertrophy were related to AHI and sleep duration, independent of BMI. Neither sleep duration nor efficiency was associated with CAC.

CONCLUSIONS

CAC was not associated with AHI, independent of BMI in a community-based sample of middle-aged men and women. Framingham risk score profiles were related to poor sleep. Sleep duration may not be related to early plaque burden in relatively healthy individuals.

High risk for sleep apnea in the Berlin questionnaire and coronary artery disease

INTRODUCTION

Obstructive sleep apnea (OSA) affects up to 30% of the adult population and is a risk factor for coronary artery disease (CAD). The diagnostic process, involving polysomnography, may be complex. Berlin questionnaire (BQ) is a validated and economical screening tool.

PURPOSE

The aim of this study was to assess the performance of the BQ for the diagnosis of OSA in individuals with angina complaints.

METHODS

Patients undergoing diagnostic cineangiography, portable type III polysomnography to determine the apnea-hypopnea index (AHI), and who answered the BQ were included. We excluded patients older than 65 years that were smokers, diabetics, and morbidly obese. High risk for OSA was based on positive responses in two of three symptom criteria of the BQ. CAD was defined by the presence of >50% lesion in coronary arteries.

RESULTS

In 57 included cases, high risk in the BQ indicates significant odds ratio [95% confidence interval] for the presence of CAD (4.5[1.03-19.25], P = 0.045), adjusted for usual confounders: gender, age, and body mass index. The sensitivity and the specificity of BQ for CAD were 70% and 48%, respectively; the positive and negative predictive values are 56% and 64%.

CONCLUSIONS

In conclusion, simple questionnaire-based diagnostic tools can be included in the screening procedures of patients with angina to detect the need for further OSA evaluation. In conclusion, the BQ is an effective instrument for this purpose.